DESCRIPTION OF CORE UNIT 1. Overview The role for this core is to support all the projects in their requirements for genome-wide expression analysis, single nucleotide polymorphism (SNP)^ analysis, gene mapping and sequencing. Support will be provided by several means with emphasis placed on: 1) Expression analysis by micro-array, 2) high volume scoring of SNP and, in some cases, microsatellite polymorphisms in humans and mice;and 3) the processing and analysis of dideoxy-terminated sequencing reactions produced by the individual projects. In addition, the core will aid the projects in the preparation of expression, genotype and sequence data in formats most useful for further analysis. These data will be formatted for forwarding to the Biostatistics Core (Core C). For followup investigation of individual genes, the core will assist the projects in qPCR and analysis by R-QTL. State-of-the-art genotyping and expression analysis, with its reliance specialized equipment and partial automation, is most efficiently carried out in a core laboratory that is staffed by experienced personnel and that is specifically organized for this work. The centralization of genotyping in Core B will both increase efficiency and decrease supply costs for the Program Project by allowing high throughput technologies and allowing bulk purchases of reagents.